LOS ANGELES — The Board of Supervisors voted today to move forward with a plan to reduce property taxes on some vacant urban lots if owners lease them out as vegetable gardens or fruit orchards.

Supervisor Mark Ridley-Thomas proposed the Urban Agriculture Incentive Zone program, saying it would boost public health and replace vacant, blighted lots with gardens full of healthy fruits and vegetables.

“This seeks to provide a carrot, literally and figuratively, to make it more financially viable to grow fruits and vegetables in the urban space,” Ridley-Thomas said.

The move to increase the number of urban gardens was enabled by a state law passed last year that gives municipalities the leeway to lower taxes on properties of three acres or less leased for agricultural use.

The tax break would run for at least five years and would apply only in to-be-designated zones of the county.

Cities within the proposed zones would have the option to opt in or out of the program. Los Angeles City Councilmen Felipe Fuentes and Curren Price have already proposed that L.A. participate.

Advocates said an urban incentive zone would increase access to food for struggling low-income families and also create jobs.

“There will always be vacant land that the free market leaves behind and there will always be labor that the free market leaves behind,” said Andrew Douglas with the Food Policy Council working group.

Last November, the board asked staffers to look at the feasibility of setting up an urban incentive zone.

In a report issued in June, the county assessor estimated that about 57,000 parcels may be eligible countywide and that roughly 8,000 of those are in unincorporated areas of the county.

If 5 percent of the total properties were to be signed up, the county would lose an estimated $6.7 million, according to the assessor. The report set the high end of likely participation at 10 percent.

Ridley-Thomas proposed a phased roll-out to study the effects and setting a cap on participation.

Douglas cautioned against creating too much red tape for those who want to grow food in their neighborhoods.

The board directed staffers to come up with a draft contract for property owners, criteria for property eligibility, the boundaries for the incentive zone and other details needed to implement the plan. A report is expected back in six months.